Sorry, you might subscribe to the no child left behind style of thinking but I don't. This is a hobby for all of us, and something we do in our free time. I don't know, or care how you view it, but I value my free time. I'd rather spend it with folks like Tuco and PRX instead of people like Tad10 who failed at doing 2 man dungeons in DC Universe.
Honestly, this is why I like big raids AND I liked the original WoW's "non uniformed" Raid/Group design. What I mean by that is that there were so many non-overlapping buffs, debuffs and auras that group set up, and even group placement (Like physically making sure one group stayed by one caster) could have a decent effect on your groups DPS/Resists and efficiency.
This, combined with the raid leader being able to select special jobs for boss moves (Like who X boss would charge to, or who gets the bomb), really allowed for a big part of the overall difficulty of raiding to be placed on a small, core group within a guild...And the rest of the players, the famed "fat" of most guilds, were just there as buff bots, DPS support and mana regen/extra healing. They weren't ESSENTIAL to the fight going well--but their presence and hitting their buttons was essential to your team having enough resources to kill the boss (They were the boots of an army).
It created a pretty good delineation between needing skill in your core group, and needing just "bodies" to fill the raid. This really felt like it allowed them to tweak difficulty (Up until Nax) to where they could make things harder, but keep it so a big chunk of your raid could be somewhat casual in their involvement of the game--or their skill. Looking back, it was nice that I could raid with our resident pot head, or our soccer mom--they were nice people, and fun to have on the raid. They weren't great players, but I didn't need them for that...I had a core group of great players to actually beat the boss. The pot head/Soccer mom were there for their buffs, extra DPS or to toss out hots to keep people stable so the big healers could burn mana in clutch situations.
Certain bosses went against this, like the asshole who attacked random people in Black Temple--but for the most part, I thought it was a great design. But they slowly changed it, by making it so it really didn't matter how you designed groups, and you needed less people, so every person had greater responsibility and you had less control over random boss targets (And they became even more brutal, so any weak players became liabilities because not only did they die, but everyone around them did as well--and your tank, because fuck you, the only switch we have to make the game harder is increase the ass rape on random moves.)
In a lot of ways, WoW's big push to make raiding more accessible, actually lead to most mid level guilds being unable to take more casual players--It was ironic, but making it easier to raid, made it harder to actually get INTO raids for a vast majority of the bad players in WoW (Which was most, if not all of them). I mean, sure, before the big raid change, very few players saw the "end game"...But almost everyone was at least in a raiding guild that was progressing, even if it was the last tier. The changes to raid design (And item design, like obsolete of previous tiers) killed that ability for "poor" players to hop into decent guilds and progress (Because there literally was no room for "fat" in the smaller raids AND doing the "last tier" became obsolete)--and I thought that was a shame. (Things DID need to be tweeked, but I think it all went in the wrong direction.)
It also lead to "difficulty switches". Without that organic method of allowing bad players to help and support good ones--Blizzard needed to literally have a "terrible mode" switch just to let people see content. That switch just hollows out the experience though. The design they had before, where more of the difficulty was about strategy/organization, I believe, should have been explored further. It's always good when a game encourages different types of players (Social/Hardcore/PvP ect) to group together and rely on each other.
Anyway, so it makes me happy hearing that they are designing 40 mans, and NOT having "size" switches.